1. Field of the Invention
The present invention relates to a camera provided with a bar code reader for reading a bar code from a roll film. The present invetion also relates to a method of automatically setting up the camera by use of the bar code. Particularly, the present invention relates to a camera having an automatic pressure plate setting mechanism for setting a pressure plate of the camera to a position determined according to the type of the loaded roll film that is read from the bar code of the loaded roll film.
2. Background Arts
ISO 120-type and 220-type rolled films are called Brownie film rolls in the art. In the 120-type, a 6 cm wide photo filmstrip is secured by an adhesive tape to a light-shielding backing paper which is longer than the filmstrip and backs the entire length of the filmstrip. The filmstrip is coiled with the backing paper around a spool. In the 220-type, short pieces of light-shielding paper, called leader and trailer papers, are spliced by adhesive tapes to opposite ends of a 6 cm wide photo filmstrip.
By replacing the long backing paper with the short leader and trailer papers in the 220-type, the 220-type roll film has got a longer filmstrip than the 120-type. In the camera, the portion of the 120-type roll film that extends in a film passageway behind the exposure frame is thicker by the thickness of the backing paper than that of the 220-type. To make sure to position the emulsion surface of the filmstrip in the proper focal plane whether it is the 120-type or the 220-type, the Brownie camera has conventionally been provided with a mechanism for adjusting the depth of the film passageway according the thickness of the film portion. That is, the depth of the film passageway is enlarged for the 120-type, and is reduced for the 220-type.
There are various known mechanisms for changing over the depth of the film passageway. In a camera known as New Mamiya 6 (a trade name, Mamiya O.P. Co., Ltd.), the pressure plate inside a back lid of the camera is rotated by 90 degrees while the back lid is open. This rotation causes the pressure plate to move backward or forward of the camera. When the pressure plate is set in the forward position for the 220-type, the pressure plate comes in contact with rails. When the pressure plate is set in the backward position for the 120-type, the pressure plate is set slightly away from the rails. In a camera known as Fuji GSW680III Professional (a trade name, Fuji Photo Film Co., Ltd.), the pressure plate is removable from a back lid while the back lid is open. The pressure plate is turned over back to front or vise versa, and attached again to the back lid, thereby changing over the depth of the film passageway. In a camera known as Fuji GA645 Professional (a trade name, Fuji Photo Film Co., Ltd.), the pressure plate is manually pushed toward the back lid and slid in the film transport direction to change over the depth of the film passageway while the back lid is open.
In the known Brownie cameras, the back lid must be opened in order to change over the position of the pressure plate to adjust the film passageway to the roll film type. Once the film roll is loaded and the back lid is closed, even if the pressure plate is set wrong, it is impossible to correct the position of the pressure plate without fogging the filmstrip. If the pressure plate is set wrong, the photographed images would be out of focus, or the filmstrip would be scratched.
Japanese Utility Model Publication No. 48-33284 discloses a Brownie camera wherein a pressure plate is movable in an optical axis direction of a taking lens of the camera by sliding a knob that is provided on an outer portion of the back lid. Also in this case, the knob is manually operated. Therefore, the problem of setting the pressure plate wrong is not cleared away.
An idea of providing a bar code on the adhesive tape connecting the filmstrip to the light-shielding paper is disclosed in U.S. patent application Ser. No. 08/712,387, that was filed based on Japanese Patent Applications No. 7-235127 et al. The bar code on the adhesive tape represents information about the roll film, such as the discrimination between the 120-type and the 220-type, the film speed. By providing the Brownie camera with a bar code reader for reading the bar code, the camera can automatically adjust to the loaded roll film.
However, the camera should be able to operate with a roll film with no bar code as well as the roll film with a bar code. Moreover, the bar code on the roll film can be difficult to read depending upon its printing condition and the condition of the adhesive tape.